We have two 7 month old long haired miniature dachshunds. A male and female, siblings from the same litter. They get on amazingly well.
When we walk them separately they well behaved, walking along beside us and little or no barking.
When we walk them together it is the opposite, barking at everything that moves, especially kids and bikes!
We've tried pulling them in a different direction and distracting with treats but the female isn't too interested in treats. We've also tried using a clicker.